Single-Crystal Choke Cage for Erosion-Resistant Flow Control
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Solution Overview
Problem
Fluid chokes in oil and gas production experience erosion and cavitation due to abrasive fluids and pressure changes, leading to degraded performance and control issues.
Innovation Solution
The use of a choke with a cage and plug system where the cage and plug are made of single crystal materials like sapphire or ruby, providing enhanced erosion resistance and lower stiction, maintaining flow characteristics and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional materials (steel, carbide) are used for the cage and plug, then the choke can be manufactured with standard materials and processes, but the surfaces experience erosion and cavitation leading to degraded performance over time
Solution Approach 1:
The patent applies composite materials by combining a substrate (cage or plug) made of conventional material with a coating layer made of single crystal material such as sapphire or ruby. This composite structure provides both the mechanical strength of the substrate and the erosion/cavitation resistance of the single crystal coating, thereby improving reliability while protecting against harmful factors.
Solution Approach 2:
The patent changes the material parameter from conventional polycrystalline materials to single crystal materials for the coating. Single crystal materials have no grain boundaries, which eliminates grain boundary erosion and provides superior resistance to cavitation and abrasion, directly addressing the durability issue.
2Adaptability or versatility
If multiple flow openings are provided in the cage, then the flow control capability is enhanced, but the surface area exposed to abrasive fluid flow increases leading to greater wear
Solution Approach 1:
The cage with multiple flow openings is coated with single crystal material to protect the increased surface area exposed to abrasive fluid flow. The composite structure allows the cage to maintain its flow control capability with multiple openings while the coating protects against wear on all exposed surfaces.
3Reliability
If the blocking mechanism is spaced from the wall to allow leakage, then the choke can prevent complete flow blockage, but fluid can leak between the blocking mechanism and wall reducing control precision
Solution Approach 1:
The patent changes the surface properties of the blocking mechanism and wall through single crystal coating, creating an ultra-smooth surface with minimal roughness. This reduces fluid leakage through the clearance while maintaining the spacing needed to prevent complete blockage, thereby improving flow control precision without sacrificing reliability.
Data Source
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AI summary
A choke includes a cage having a plurality of openings extending therethrough, a first fluid port and a second fluid port, the openings in the cage fluidly interposed between the first and second fluid ports, and a selectively positionable blocking member positioned with respect to the openings to selectively overlie all of a portion of the openings, wherein the surface of the opening extending through the cage are a single crystal material. The single crystal material may be provided as an insert, having an opening therethrough, secured in position with respect to the cage.